Problem: If $x \oslash y = 7x+y$ and $x \boxdot y = 2x-8$, find $2 \oslash (-1 \boxdot -1)$.
First, find $-1 \boxdot -1$ $ -1 \boxdot -1 = (2)(-1)-8$ $ \hphantom{-1 \boxdot -1} = -10$ Now, find $2 \oslash -10$ $ 2 \oslash -10 = (7)(2)-10$ $ \hphantom{2 \oslash -10} = 4$.